There are many different types of grips used today for a wide variety of items, including without limitation, golf clubs, tools (hammer handles, screwdrivers, etc.), racquets (racquet ball, squash, badminton, or tennis racquets), bats (baseball or softball), pool cues, umbrellas, fishing rods, etc. While particular reference for this disclosure is being made to the application of golf club grips, it should be immediately apparent that the present disclosure is applicable to other grips as well.
Slip-on golf club grips made of a molded rubber material or synthetic polymeric materials are well known and widely used in the golf industry. The term “slip-on” as employed herein refers to a grip that slides on to a shaft or handle and is secured by way of an adhesive, tape, or the like. Slip-on grips are available in many designs, shapes, and forms.
Golf club grips historically have been made of a wide variety of materials such as leather wrapped directly on the handle or leather wrapped on sleeves or underlistings that are slipped on to the handle, or more recently rubber, polyurethane or other synthetic materials are used. Up until now, various construction methods have been used to produce a lower overall material density. Most commonly, an inner structure is formed using a light weight foam material, often EVA foam. Over this structure, a gripping layer is located and held in place through the use of either an adhesive or some other bonding method. Most commonly, this gripping layer is made from a felt material where the outside is coated in polyurethane to provide a smoother and more durable outer layer. Another existing method of manufacturing a lightweight structure to form a grip is to use expanded foam/sponge material tubes (EVA, nitrile rubber, etc.) molded, or ground, to shape. These foam/sponges also have relatively low abrasion and UV resistance, tend to wear out more quickly than traditional rubber grips, and may take on a permanent compression set over time leaving permanent depressions in the golf grip, thereby risking a potential violation of the rules of golf.
There is a trend in golf toward lighter weight. Swing grips, as used on clubs such as woods and irons, that are light weight offer the golfer enhanced performance by generally facilitating a faster club head speed. Further, there is a trend in non-swing grips, or putter grips, to oversized grips that provide a more stable grip and help prevent the wrists from becoming too active during a putting stroke. While the size of such grips increases, it is desirable to maintain the weight of the grip consistent with non-oversized grips so the balance and swing weight of the putter is maintained.
It is also desirable to offer golf grips in multiple colors. A multiple color grip is more attractive and gives the brand an identity for instant brand recognition. When molding a golf grip in multiple colors it is desirable to form a defined border between the colors that is consistent in location and shape. The defined border may be a straight line, an angled line, a curved line, or any desired geometry. The defined border between colors increases the perceived product quality and brand identity. However, this is difficult to achieve such a defined border with light weight rubber molding because the materials are not stable at the lower densities needed to achieve the desired grip weight.
It is desirable to produce lightweight multicolor compression molded grips using rubber compounds. Rubber has a good feel and is preferred by golfers. However, rubber is a heavy material with a density of approximately 1.2 g/cc. In order to reduce the density, lightweight materials must be added to the rubber compound, which further increase the difficulty of achieving a defined border. Thus, there still exists a need for a lightweight multicolor compression molded grip having a sharply defined interface between the colors, particularly one that is soft, resilient, and resistant to permanent deformation and the associated risks.